Mobile service providers typically collect usage information using server-side techniques. One techniques is to track downloads from a WAP portal/web-server when users visit a web-site optimized for viewing on the mobile phone. A drawback of this technique is that it does not provide fine-grained information regarding how users actually consume the content. Such information would be useful in order to better tailor service offerings to user needs. Another technique for collecting usage information is by tracking the delivery of SMS (Short Message Service) messages. A drawback of this technique is that it typically assumes that the recipient views each SMS message that is delivered. This assumption can be very inaccurate, however, since many users delete spam SMS messages without viewing them.
In the absence of reliable usage information, a common form of mobile advertising is via SMS spamming. In many locales where incoming SMS messages are free, advertisers purchase bulk SMS sending capacity and spam users with SMS advertisements. Users often delete these advertisements without viewing them. Some evidence suggests that some consumers do not want to pay for content but would be willing to watch advertisements in exchange for not paying for the content. Some consumers even enjoy watching advertisements.